[tepl] build: add comment

[Sébastien Wilmet <swilmet src gnome org>]

commit 10a2d27c41b3c8ae5e696aded309b020ebdcf17e
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon May 4 16:00:11 2020 +0200

    build: add comment
    
    See commit b2fed72be4178dc074afd0ac9b1aea5f37c24413 (by Xavier Claessens).

 tepl/meson.build | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/tepl/meson.build b/tepl/meson.build
index a8b6d3b..c5acad2 100644
--- a/tepl/meson.build
+++ b/tepl/meson.build
@@ -160,6 +160,8 @@ TEPL_LIB_DEP = declare_dependency(
   dependencies: TEPL_DEPS
 )
 
+# pkg-config file generation. Supports GtkSourceView being built as a
+# subproject.
 PKG_CONFIG.generate(tepl_lib,
   filebase: 'tepl-@0@'.format(TEPL_API_VERSION),
   name: 'Tepl',